Working Papers

One of the central predictions of the life cycle hypothesis is that individuals smooth consumption over their economic life cycle; thus, they save when income is high, in order to provide for when income is likely to be low, such as after retirement. We test this prediction in a group of people—players in the National Football League (NFL)—whose income profile does not just gradually rise then fall, as it does for most workers, but rather has a very large spike lasting only a few years. We collected data on all players drafted by NFL teams from 1996 to 2003. Given the difficulty of directly measuring consumption of NFL players, we test whether they have adequate savings by counting how many retired NFL players file for bankruptcy. Contrary to the life-cycle model predictions, we find that...

We investigate the feasibility of inferring the choices people would make (if given the opportunity) based on their neural responses to the pertinent prospects when they are not engaged in actual decision making. The ability to make such inferences is of potential value when choice data are unavailable, or limited in ways that render standard methods of estimating choice mappings problematic. We formulate prediction models relating choices to "non-choice" neural responses and use them to predict out-of-sample choices for new items and for new groups of individuals. The predictions are sufficiently accurate to establish the feasibility of our approach.

We use measures of neural activity provided by functional magnetic resonance imaging (fMRI) to test the "realization utility" theory of investor behavior, which posits that people derive utility directly from the act of realizing gains and losses. Subjects traded stocks in an experimental market while we measured their brain activity. We find that all subjects exhibit a strong disposition effect in their trading, even though it is suboptimal. Consistent with the realization utility explanation for this behavior, we find that activity in the ventromedial prefrontal cortex, an area known to encode the value of options during choices, correlates with the capital gains of potential trades; that the neural measures of realization utility correlate across subjects with their individual tendency ...